NAME
tcgetpgrp() — get foreground process group id
SYNOPSIS
#include <unistd.h>
pid_t tcgetpgrp(int fildes);
DESCRIPTION
tcgetpgrp()
returns the value of the process group
ID
of the foreground process group associated with the terminal referenced by
fildes.
tcgetpgrp()
is allowed from a process that is a member of
a background process group (see
termio(7));
however, the information can be subsequently changed by a process
that is a member of a foreground process group.
RETURN VALUE
Upon successful completion,
tcgetpgrp()
returns the value of the process group
ID
of the foreground process group associated with the terminal referenced by
fildes.
Otherwise,
tcgetpgrp()
returns a value of -1 and sets
errno
to indicate the error.
ERRORS
tcgetpgrp()
fails if any of the following conditions are encountered:
- [EACCES]
The file associated with
fildes
is the controlling terminal of the calling process,
however, there is no foreground process group defined
for the controlling terminal.
- [EBADF]
fildes
is not a valid file descriptor.
- [ENOTTY]
The file associated with
fildes
is not the controlling terminal or the calling process
does not have a controlling terminal.
APPLICATION USAGE
tcgetpgrp()
is thread-safe and async-cancel-safe.
WARNING
The error
EACCES,
which is returned if the controlling terminal
has no foreground process group,
might not be returned in future releases,
depending on the course taken by the
POSIX
standard.
Portable applications therefore should not rely on this error condition.
STANDARDS CONFORMANCE
tcgetpgrp(): AES, SVID3, XPG3, XPG4, FIPS 151-2, POSIX.1
